Characteristics and the behavior in electrostatic precipitators of high-alumina coal fly ash from the Jungar power plant, Inner Mongolia, China

In China, flue gases emitted by coal-fired power plants are mainly cleaned using electrostatic precipitators (ESPs). However, based on observations, there is a decrease in the collection efficiency of ESPs in some power plants after burning Jungar coal in Inner Mongolia. In order to find the mechanism of coal fly ash escaping from ESPs, the size distribution, resistivity, and cohesive force of particulate matter samples from Jungar coal-fired power plants in China were measured using a Bahco centrifuge, a dust electrical resistivity test instrument, and a cohesive force test apparatus invented by the authors. Experiments were carried out to determine the chemical composition and current-voltage curve of fly ash under operating ESPs. The Al(2)O(3) content in fly ash was found to reach more than 50%, with the size distribution showing a higher content of PM2.5 and PM10 in high-alumina coal fly ash than in other coal fly ashes. The resistivity of high-alumina coal fly ash was recorded at over 10(12) Omega cm, but this did not result in a clear back corona. The cohesive force of high-alumina coal fly ash was very little. It was sensitive to smoke speed in the electric field, facilitating dust re-entrainment. (C) 2011 Elsevier B.V. All rights reserved.